The measurement was taken at the end of the first confinement.
Put back on the table before Christmas.
And again claimed by the scientific council in its last opinion in mid-January.
Generalized curfew, strict or adapted confinement ... "Whatever the scenario adopted by the health authorities, the scientific council advises the implementation of a limitation of interregional movements", write the experts responsible for guiding the executive.
If the government has finally favored the closure of major shopping centers and borders, could the return to the 100 km rule be effective in countering the dreaded effects of going on vacation?
The question divides.
"I am not convinced," says François Bricaire, infectious disease specialist and member of the Academy of Medicine.
If you take the car to go from Paris to Versailles, in my opinion the risk is the same as going to Cantal.
"
Preserving the least affected regions
According to the professor, this restriction of movement is an empirical measure: “I ask to see the evidence of its effectiveness.
As for the idea of limiting flows as the February holidays approach, he is also skeptical here.
“If it's to prevent people from going on vacation, I don't think it's necessarily good for the morale of children and parents.
We must give them the opportunity to move, to breathe, to live, "he supports, a supporter of decisions" at the right times "depending on the evolution of the epidemic.
However, this 100 km rule has the advantage of preserving the regions least affected by the virus, argues Pierre Tattevin, the president of the French-speaking Society of Infectious Pathology.
Although the situation in France is less heterogeneous than in the spring, strong disparities currently exist between the Alpes-Maritimes, marked by an incidence rate of 450, the Côtes-d'Armor at 60 or even Paris at 230.
"Restricting movement makes it possible to limit the spread of the virus in regions still spared and thus allow them to welcome patients from areas under stress to relieve hospitals", assures Pierre Tattevin.
On Thursday, interregional transfers resumed and two patients from the Nice University Hospital were transported to the other end of France, to Brittany, to Vannes (Morbihan).
A relevant measure against variants?
But where this measurement can prove to be “even more relevant”, says the infectious disease specialist, “it is if we notice that the variants circulate differently from one region to another”.
And it just might be.
“To find out, we have to wait for the results of the second Flash study.
But the analysis of 1080 positive PCR tests, between January 11 and 21 in eight screening sites in Ile-de-France, has already shown that the English variant represented 9.4% of the cases tested against 1%, two weeks ago.
It's enormous!
This is the stake.
Two scenarios are possible, argues the mathematician Jean-Stéphane Dhersin, deputy scientific director at the CNRS: in the first, the variant progresses in the same way as the historical strain, in the second it spreads as quickly as in the United Kingdom.
“In the latter case, the situation will be untenable in March and the current measures insufficient.
Among the range of decisions, limiting travel works very well when there is great territorial heterogeneity.
"
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Is it the most relevant?
Impossible to know, answers the scientist.
“Every measure aimed at lowering the rate of reproduction of the virus is effective, but we do not know in what proportion.
The level of circulation of variants will therefore be decisive.
Jean-Stéphane Dhersin sums it up.
“If the epidemic flares up, we will have to act but for the moment, we do not know with what force it will be necessary to strike.
"